The present invention relates to tubes used in heat exchangers and, more particularly, to an apparatus and method for sizing the tubing and also positioning and installing manifolds to couple flat tubes to round tubes.
In the fabrication of heat exchangers, extruded tubing with internal webs is frequently used to conduct a working fluid through a path in the heat exchanger. Sometimes, numerous tubes are networked together to form a plurality of paths. At each end of the pathway, a means must be provided to channel the working fluid to a common entrance or exit of the heat exchanger. This is often accomplished using a manifold. In one manifold design, the manifold channels the working fluid from two oval extruded tubes to a common round inlet/outlet. It is important that the extruded tubes be inserted into the manifold with the clearance between the tubes and the manifold opening no larger than suitable for the subsequent brazing operation. The manifold must also be installed square with the core and remain so until the braze operation is complete. Unfortunately, the extruded tubing in most instances has dimensional tolerances too large for consistent tube-to-manifold clearance.
In many heat exchangers, the tubes are inserted through a common manifold and brazed to form a one-piece assembly. For satisfactory installation of the manifold, the tubes must be sized down to an acceptable dimension for insertion into the manifold. It is important, too, that the braze joint formed not posses any voids which may form leaks. In particular, heat exchangers are designed to use tubes of various perimeter dimensions. However, the ends of the cut tube must be sized to fit snugly into the hole of an end fitting, regardless of the perimeter dimensional tolerances of the ends of the tubing.
It is seen then that there exists a need for an apparatus and method for sizing tubing and also positioning and installing manifolds to quickly and easily couple tubes having varying perimeter dimensions to various manifolds.